Process of producing ferrosilicon



seventy UNITED STATES PATENT OFFICE.

JOHN TYLER JONES, OF PITTSBURGH, PENN SYLVANIA,'ASSIGNOR TO THOMAS J. HOWELLS, OF PITTSBURGH, PENNSYLVANIA.

PROCESS OF PRODUCING FERROSILIGON.

No Drawing.

To all whom it may concern:

Be it known that I, JOHN TYLER J ONES, a citizenof the United States, and a resident of Pittsburgh, in the county. of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Processes of Producing Ferrosilicon, of which the following is a specification. v

Myinvention relates to improvements in processes for the product-ion of ferrosilicon, and it consists in the steps hereinafter described and claimed.

An object of my invention is to provide an economical process for the production of ferrosilicon, the product serving admirably as a hardener or a deoxidizer.

A further object of my invention is to provide a process for the production of ferrosilicon which may be carried out quickly, thereby resulting in a saving of time as Well as in cost.

A further object of my invention is to provide a process for making ferrosilicon which does not require the use of specially designed machinery to carry out the process, but which may be carried out through the use of ordinary apparatus such as a regenerative coking oven and a regenerative furnace.

Other objects and advantages will appear in the following specification and the novel features of the invention will be particularly pointed out in the appended claims.

In carrying out my invention, I make use of silicious iron-ore such as that found in Iron county, Michigan, in which the silica and iron oxid are approximately evenly divided, that is to say, fifty per cent. being silica and fifty per cent. iron oxid with traces of other minerals such as potassium, lime, magnesium. These deposits will occur in veins dgenerally having an inclination of egrees. The ore containing the iron and silicon .in their oxid forms, is first crushed by means of any suitable crushing device, to a fineness which ap roximates twenty'to one hundred mesh. referably bituminous coal of a quality which has thirty-six per cent. (36%) of volatile matter, and sixty per cent. of fixed carbon, the remainder being various organic and inorganic constituents, is crushed to a corresponding fineness, that is to say, substantially twenty mesh, although the crushing of the coal Specification of Letters Patent.

Application filed October 26, 1917. Serial No. 198,673.

to the same fineness is not absolutely nec essary. The crushed ore and the crushed coal are now mixed in any suitable mixing device such as a rotating barrel or the like, and are thoroughly intermingled. It is necessary that an excess of coal be used and the proportions which are preferably used are one-third of ore and two-thirds of coal, although these proportions may be varied without departing in the least from the spirit and scope of the invention. The mixed material is now put into a furnace or retort and heated. The particular kind of retort forms no part of the present invention; An ordinary Siemens regenerative coking oven or an ordinary by-product oven may be used and the temperature at which the mixture is heated is preferably the highest temperature ordinarily used in making coke.

The material, that is to say, the mixed coal and ore is left in the oven long enough to thoroughly coke the mass. The time depgnds, of course, upon the size of the oven.

ith some ovens twenty-four hours is sufficient, while other require forty-eight and others perhaps, seventytwo. When the mixed ore and coal is put in a small crucible and heated the mass is coked in a few minutes.

I have spoken of bituminous coal as bemg preferably .used in this process; any

hydrocarbon bearing material which on being heated gives off volatile gases capable of igniting for combustion, and which will leave'the material which bears the volatile matter in practically a coked state, may be used without departing from the invention.

After the material has been coked it is taken out of the oven in a red-hot condition and water is turned on it as in the ordinary process of making coke. The product is a substance whichhas very much the appearance' of coke. On closer examination, however, itwill be found that the metal is in a metallic state, that is to say, instead of being in the oxid form, it is in the metal form and the oxygen has been substantially driven off. Furthermore, the metals tobe recovered by the process are not in an alloyed state yet. They exist in finely separated'metal particles, these particles belng separated by portions of the coke itself, so that the silicon and iron have not yet combined in the coked mass.

After the coked product has cooled, it is put into an ordinary melting furnace, such as an open hearth furnace or blast furnace, and the coke is burned off. Simultaneously with the burning off of the coke, the metals are melted and the product is a ferrosilicon of substantially the same proportions of metal that existed in the ore. In order to get a ferrosilicon having metal proportions desired, ore containing those proportions may be mixed and then treated. Of course, some of the ore has more iron in it, and some more silicon. As a matter of fact, if it is desirable to have more silicon in the resulting product, ordinary sand may be used and may be mixed with the ore and treated as above described.

I desire to call particular attention to the fact that substantially no air is admitted to the mixed ore and-coal while the matter is undergoing the first treatment, that is to say, while it is being brought into a coked condition. Neither are fluxes used.

The process described herein, it will be noted, requires that'the ore be in a finel divided state. The whole tendency of mo ern metallurgy, at least up to the present time, has been to get away from the finely divided state, that is to say, to carry out the operation with lumps of ore, not with small particles of ore or ore dust. The dust in the ordinary operation is blown out of the furnace, while in the present process I make use of every bit of the crushed material. The finer the material, the better is the product.

I claim:

1. The herein described process of producing ferrosilicon, whichconsists in crushing the ore to a fineness approximating twenty to one hundred mesh, crushing bituminous coal to substantially the same fineness, mixing an excess of the coal with the ore, heating the mixture substantially out of the presence of air, to coke the coal and mixture to a temperature sufficient to coke the coal, thereby producing a coke-like agglomerated mass containing iron in metallic form and silicon in metallic form, the particles of iron being separated from the particles of silicon by intervening particles of coke, and subsequently burning thecoke in the presence of air, and melting the metal into the alloy.

JOHN TYLER JONES. 

